The present invention relates to a fiber composite material and a method of producing the same.
A composite material is generally provided with physical properties corresponding to the application by combining a matrix material and reinforcing fibers or particles. In the fields of semiconductor manufacturing instruments, optical instruments, microprocessing instruments, and the like, a reduction in the effects of thermal expansion of parts has been demanded. To deal with this demand, various composite materials using reinforcing fibers such as carbon fibers have been proposed (see WO 00/64668, for example).
However, it is difficult to provide a composite material using fibers with a thermal expansion isotropy in comparison with a composite material using particles. Therefore, the application is limited to a product in the shape of a sheet or a plate, or a three-dimensional structure such as a biaxial or triaxial weave must be formed using fibers. The coefficient of linear expansion of an elastomer changes to a large extent under different temperature conditions. In particular, since an elastomer thermally deteriorates at a relatively low temperature due to molecular chain scission, the coefficient of linear expansion rapidly increases in the vicinity of such a temperature (the temperature at which thermal deterioration starts is hereinafter called “heat resistant temperature”). Therefore, a composite material using an elastomer matrix which exhibits a low and stable coefficient of linear expansion over a wide temperature range has not been proposed.
The inventors of the invention have proposed a fiber composite material in which carbon nanofibers are uniformly dispersed (e.g. JP-A-2005-68386). In this fiber composite material, the dispersibility of the carbon nanofibers exhibiting high aggregating properties is improved by mixing the elastomer and the carbon nanofibers.